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Add Sub Integers

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How to Add and Subtract Integers

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Add Sub Integers

  1. 1. Adding and Subtracting Integers <ul><li>Downloaded and Modified from </li></ul><ul><li>Algebra 1 Online! </li></ul><ul><li>http://teachers.henrico.k12.va.us/math/HCPSAlgebra1/index.html </li></ul>
  2. 2. The Number Line <ul><li>Natural Numbers = {1, 2, 3, …} </li></ul><ul><li>Whole Numbers = {0, 1, 2, …} </li></ul><ul><li>Integers = {…, -2, -1, 0, 1, 2, …} </li></ul>-5 0 5
  3. 3. To GRAPH a set of numbers means to locate and mark the points on the number line. <ul><li>Graph {-1, 0, 2}. </li></ul><ul><li> • • • </li></ul><ul><li>Be sure to put the dots on the line - not above or below. </li></ul>0 5 - 5
  4. 4. Addition and Subtraction Rules <ul><li>When the signs are the same, ADD </li></ul><ul><li>and keep the sign. </li></ul><ul><li>2 + 4 = 6 </li></ul><ul><li>-2 – 4 = -6 </li></ul><ul><li>When the signs are different, SUBTRACT and use the sign of the larger number. </li></ul><ul><li>-2 + 4 = 2 </li></ul><ul><li>2 – 4 = -2 </li></ul>
  5. 5. What’s the difference between 7 - 3 and 7 + (-3) ? <ul><li>7 - 3 = 4 and 7 + (-3) = 4 </li></ul><ul><li>The only difference is that 7 - 3 is a subtraction problem and 7 + (-3) is an addition problem. </li></ul><ul><li>“ SUBTRACTING IS THE SAME AS ADDING THE OPPOSITE.” </li></ul>
  6. 6. When Signs Are Next to Each Other <ul><li>Same signs next to each other = PLUS </li></ul><ul><li>2 + (+4) = 2 + 4 = 6 </li></ul><ul><li>2 – (-4) = 2 + 4 = 6 </li></ul><ul><li>Different Signs next to each other = MINUS </li></ul><ul><li>2 + (-4) = 2 – 4 = -2 </li></ul><ul><li>2 – (+4) = 2 – 4 = -2 </li></ul>
  7. 7. More Examples <ul><li>Example #1 : - 4 - (-7) </li></ul><ul><li>- 4 + 7 </li></ul><ul><li>Diff. Signs --> Subtract and use larger sign. </li></ul><ul><li>3 </li></ul><ul><li>Example #2 : - 3 + ( - 7) </li></ul><ul><li>- 3 - 7 </li></ul><ul><li>Same Signs --> Add and keep the sign. </li></ul><ul><li>-10 </li></ul>
  8. 8. Karaoke Time! <ul><li>Addition Rule: Sung to the tune of “Row, row, row, your boat” </li></ul><ul><li>Same signs add and keep, different signs subtract, keep the sign of the higher number, then it will be exact! </li></ul>
  9. 9. -1 + 3 = ? <ul><li>-4 </li></ul><ul><li>-2 </li></ul><ul><li>2 </li></ul><ul><li>4 </li></ul>Answer Now
  10. 10. -6 + (-3) = ? <ul><li>-9 </li></ul><ul><li>-3 </li></ul><ul><li>3 </li></ul><ul><li>9 </li></ul>Answer Now
  11. 11. 11b + 2b Same Signs --> Add and keep the sign. 13b Okay, here’s one with a variable! Example #3 : 11b - (-2b)
  12. 12. Which is equivalent to -12 – (-3)? <ul><li>12 + 3 </li></ul><ul><li>-12 + 3 </li></ul><ul><li>-12 - 3 </li></ul><ul><li>12 - 3 </li></ul>Answer Now
  13. 13. 7 – (-2) = ? <ul><li>-9 </li></ul><ul><li>-5 </li></ul><ul><li>5 </li></ul><ul><li>9 </li></ul>Answer Now
  14. 14. Absolute Value of a number is the distance from zero. Distance can NEVER be negative! The symbol is |a|, where a is any number.
  15. 15. Examples  7  = 7 10 100  10  =  -100  =  5 - 8  =  -3  = 3
  16. 16. |7| – |-2| = ? <ul><li>-9 </li></ul><ul><li>-5 </li></ul><ul><li>5 </li></ul><ul><li>9 </li></ul>Answer Now
  17. 17. |-4 – (-3)| = ? <ul><li>-1 </li></ul><ul><li>1 </li></ul><ul><li>7 </li></ul><ul><li>Purple </li></ul>Answer Now

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